The present invention relates generally to operations performed in conjunction with subterranean wells and, in an embodiment described herein, more particularly provides a method and system for downhole selection of hydraulic paths for operation of tools.
A need exists for reducing the expense, and correspondingly increasing the speed and convenience, of operating tools, such as flow control devices, in a well. For example, for a producing well, it is somewhat costly to rig up a slickline or wireline unit at the well in order to adjust a downhole choke, or to open or close a valve downhole. It would be far less costly to be able to make such adjustments by applying fluid pressure at the earth's surface in order to cause an adjustment of a choke, opening or closing of a valve, etc.
It is, of course, well known to extend control lines from downhole tools to the earth's surface, so that the tools may be operated by applying fluid pressure to one or more of the lines to operate selected ones of the tools. Unfortunately, where there are multiple such tools, it quickly becomes cumbersome, time-consuming and expensive to install the control lines. Additionally, where a tool is positioned relatively deep in a well, the expense of the lines increases dramatically, as does the probability that the lines will become damaged during installation or thereafter.
One method of performing well servicing operations without the need of rigging up a slickline or wireline unit is provided by the TFL ("through flowline") system developed by Otis and now available from Halliburton Energy Services, Inc. In this system, various items of equipment are circulated into a well through one or more flowlines, which may be production tubing strings. The equipment, once delivered into a well, is capable of performing a variety of operations, such as making adjustments to flow control tools, paraffin cutting, etc. However, although the TFL system does provide a means of operating a mechanically operable tool by application of fluid pressure to certain TFL equipment, it does not at present provide a means for selecting a hydraulically operable tool for actuation thereof.
From the foregoing, it can be seen that it would be quite desirable to provide a well system and method of operating downhole hydraulically operable tools, and specifically of selecting such tools for operation thereof. The method should not require the use of control lines extending large distances. Additionally, the method should not require the use of a slickline or wireline rig, although embodiments of the method may permit such use of a slickline or wireline rig. For use in highly deviated wells, or in other circumstances, the method may also permit use of a coiled tubing rig to perform the tool selection, deliver fluid or fluid pressure, etc.